FR2756830A1 - FLUORINATED HYDROPHILIC POLYMERS - Google Patents

Abstract

The fluorinated hydrophilic polymers according to the invention are obtained by radical polymerization, in a precipitating medium, of a mixture of monomers composed of at least one nonionic hydrophilic monomer, at least one monomer with a perfluoroalkyl side chain and, optionally, of one or more ionic or ionizable hydrophilic monomer (s). These polymers are particularly useful as thickeners and as additives in multipurpose fire-fighting foam concentrates.

Description

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DESCRIPTION

  The present invention relates to the field of hydrophilic polymers and to

  more particularly for subject hydrophilic fluoropolymers obtained by poly-

  radical meritization in a precipitating medium of nonionic hydrophilic monomers, of perfluoroalkyl side chain monomers and, optionally, of ionic or ionizable hydrophilic monomers. These polymers lower the surface tension

  aqueous solutions; they are good foaming agents and they are more particularly

  particularly interesting as thickeners and as additives in

  Versatile fire-fighting foam concentrates.

  Hydrophilic polymers and more particularly those based on acryla-

  mide, methacrylamide or their N-substituted derivatives are well known and widely used industrially. Very often acrylamide, methacrylamide and their derivatives are copolymerized with other hydrophilic monomers carrying

  ionic or ionizable charges, anionic or cationic, which give the poly-

  hydrophilic mother of specific properties adapted to each application. These polymers are commonly used in the paper industry, in water treatment and in metallurgy as flocculants of ores; they are also used as thickening agents in many formulations such as

  textile printing and cosmetic products.

  The most used methods for preparing these polymers use aqueous media; this is the case for aqueous solution polymerization or micellar polymerization, but other methods such as reverse emulsion polymerization are also practiced. The polymerization is generally initiated by a redox couple generating radicals such as, for example, the persulfate (S2082 -) / metabisulfite (S2052-) couple, but also by the initiators of

  azo or peroxide radicals. Other priming systems can be used.

  such as UV rays, X-rays, ultrasound, cobalt salts.

  The copolymerization of acrylamide, methacrylamide and their derivatives in a precipitating medium, in which the monomers are soluble and the polymer precipitates during its formation, is a more rarely used and described method.

  in particular in the patents FR 1 508 702, GB 1 328 742 and US 3 336 269.

  Acrylamide, methacrylamide and their derivatives can also be copolymerized with water-insoluble monomers having a chain

  lateral hydrophobic hydrocarbon such as, for example, acrylates or metha-

  fatty alcohol crylates. The copolymers thus formed are associative thickeners, the hydrophobic groups of which in aqueous solution tend to

  form intermolecular associations thus creating a transient network. In solu-

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  tion, the viscosity of these associative polymers depends on the shear rate-

  is lying; the viscosity decreases and the solution has a pseudoplastic character, that is to say that its viscosity decreases with the increase in the shear rate. Such products are described in references [1] to [3], the list of which appears after the examples of the present application. Acrylamide, methacrylamide and their derivatives can also be copolymerized with monomers having a hydrophobic perfluoroalkyl side chain such as, for example, the acrylates or methacrylates of fluorinated alcohols. The synthesis and characterization of such hydrophilic fluoropolymers are described by Thieo E. Hogen-Esch and his collaborators and by other authors in references [4] to [12]. These fluorinated copolymers have been prepared in an aqueous medium in the presence of a co-solvent such as acetone [4] - [9], and more rarely in the medium

  aqueous in the absence of co-solvent [12] or in mass [9], the polymerization reaction

  tion having been initiated by a redox couple precursor of radicals by redox-

  tion [4] - [9], by a radical initiator precursor of radicals by thermal decomposition [9] - [12] or by triphenylmethyl cesium in anionic polymerization in solution in tetrahydrofuran. US Pat. No. 4,891,306 describes hydrophilic fluorinated copolymers obtained by anionic or cationic polymerization; these

  products are used in light sensitive photographic materials.

  In all the cases mentioned above, the hydrophilic fluorinated copolymers are synthesized in bulk or in an aqueous medium in the presence of surfactants whose purpose is to dissolve the hydrophobic fluorinated monomers inside the micelles. The surfactants preferably used are fluorinated surfactants whose perfluoroalkyl side chain is compatible with the fluorinated monomers, which allows the solubilization of these monomers. The hydrophilic fluoropolymers obtained by polymerization in an aqueous medium have as common characteristic a high molecular weight which leads to very viscous aqueous solutions, hence the use of such products as viscosifying agents. In many cases, the

  presence of fluorinated surfactants is troublesome for the subsequent use of polymers

  res, which requires resorting to precipitation of the polymer in a large excess of solvent, followed by washing of the polymer. This precipitation and washing step, which is added to the synthesis, must be carried out with large quantities of solvents, such as alcohols, which increases the manufacturing cost and produces effluents loaded with surfactants. In the case of polymerization in a precipitating medium, used in the context of the present invention, it is much easier and faster to recover the polymer in the form of a powder. Although starting from monomers of the same kind as those described above, namely derivatives of

  acrylamide or methacrylamide and perfluoroal side chain monomers

  -3- kyle, the hydrophilic fluoropolymers forming the subject of the present invention differ from the preceding ones by several aspects, the main ones of which are the process of preparation itself, the content of fluorinated monomers incorporated in the

  polymer and the nature of the radical initiating agents. These differences are reflected

  feels by very different behavior from the point of view of application properties.

  The hydrophilic fluoropolymers according to the invention can for example be

  ple used as additives in multipurpose fire-fighting foam concentrates, i.e. foam concentrates intended for extinguishing hydrocarbon fires and

polar liquids.

  Fire-fighting foam concentrates containing hydrophilic fluoropolymers have already been described, in particular in patents FR 2 438 484, US 4 563 287 and US 4 606 832. However, contrary to what is indicated in these patents, it is not it is not necessary for the fluorine content in the polymer according to the invention to be greater than or equal to 10% by weight in order to observe the influence of the groups

  perfluoroalkyl. In fact, the hydrophilic fluoropolymers according to the invention present

  try very good application performance even if their fluorine content is lower

less than 10% by weight.

  According to the indications of patent FR 2 438 484, it is not possible to form stable foams on the surface of a polar liquid if the fluorine content of the hydrophilic fluoropolymer is less than 10% by weight. However, with the hydrophilic fluoropolymers according to the invention, it is possible to obtain stable foams on polar liquid even if the fluorine content of the polymer is less than 10% in

  weight. The performance obtained on polar liquid with hydrophilic polymers

  the fluorines according to the invention come not only from their composition, but also from the method of preparation; these polymers must be prepared in a precipitating medium, that is to say in a solvent capable of dissolving the monomers

  but in which the polymer obtained is insoluble.

  Acrylamide, methacrylamide and their N-substituted derivatives, used in

  the scope of the present invention, and the method of polymerization in a precipitated medium

  are not mentioned in US Pat. No. 4,563,287 which, for the extinction of

  cooking oil fires, describes non-foaming compositions while the emulsifiers

  sors containing a hydrophilic fluoropolymer according to the present invention are

foaming compositions.

  The extinguishing compositions described in US Patent 4,606,832, also

  intended to fight cooking oil fires, use bromofluo-

  rohydrocarbons and / or bromochorofluorohydrocarbons which is not the case in -4-

  the present invention, and are not fire-fighting foam concentrates having properties

  foaming tees as in the case of the present invention.

  Patent FR 2 438 484 which does not mention acrylamide, metha-

  crylamide or their N-substituted derivatives, indicates that the polymers can be obtained by solution polymerization. Now, the solution polymerization applied to the hydrophilic fluoropolymers according to the invention does not lead to high-performance products; it is necessary to use polymerization in a precipitating medium.

  Given the high cost of fluorinated monomers compared to mono-

  hydrophilic mothers such as acrylamide, methacrylamide and their derivatives, it would be economically very advantageous to have available a hydrophilic fluoropolymer and a method for preparing it such that the properties are manifested even when

  the fluorine level is low, that is to say less than 10% by weight.

  Such a product has now been developed by the Applicant and it consists of a hydrophilic fluoropolymer, obtained by radical polymerization in

  medium precipitating at least one non-ionic hydrophilic monomer such as acryla-

  mide, methacrylamide and their derivatives, of at least one perfluoroalkyl side chain monomer and, optionally, of one or more ionic or ionizable hydrophilic monomers. Such a polymer has foaming properties; he

  lowers the surface tension of aqueous solutions and is particularly suitable for

  used as an additive in multi-purpose fire-fighting foam concentrates, that is to say foam concentrates intended to combat hydrocarbon fires and polar liquid fires. The method used to prepare these hydrophilic fluoropolymers is

  polymerization in a precipitating medium; it has the advantage of generating poly-

  mothers of low molecular weight, therefore slightly viscous products, to use a single solvent which can easily be regenerated and reused, and not to require the use of surfactants which could interfere with the application and which should therefore be extract from the medium. Depending on the operating conditions such as the relative contents of the various monomers, the concentration of radical initiator, the total initial concentration of monomers and the polymerization temperature, it

  it is possible to obtain a whole range of polymers according to the invention which differ

  according to their molecular weight, their fluorine content and their charge rate

anionic and / or cationic.

  The present invention therefore relates to hydrophilic fluorinated polymers obtained by radical polymerization, in a precipitating medium, of a mixture of monomers composed by weight of: (a) 50 to 98% of at least one nonionic hydrophilic monomer, - 5- (b) 2 to 25% of at least one monomer containing a perfiuoroalkyl radical, and optionally (c) up to 30% of one or more hydrophilic ionic or ionizable monomers. As nonlimiting examples of nonionic hydrophilic monomers (a), there may be mentioned:

  - N-vinyl pyrrolidone-2 and its derivatives, such as N-vinyl methyl-3 pyrroli-

  done-2, N-vinyl methyl-4 pyrrolidone-2, N-vinyl methyl-5 pyrrolidone-2, N-

  vinyl dimethyl-3,3 pyrrolidone-2; - ethylene glycol acrylate or methacrylate;

  - polyethylene glycol or poly ether acrylates or methacrylates

  ethylene glycol corresponding to the general formula: CH2 = CR1-CO (OCH2CH2) k OR (I) in which R represents a hydrogen atom or a methyl or ethyl radical, k is an integer ranging from 1 to 10 and R1 represents a hydrogen atom or methyl radical; - acrylamide, methacrylamide and their N-substituted derivatives corresponding to the following general formula: CH2 = CR1-CONR2R3 (II) in which R1 has the same meaning as above, the symbols R2 and R3, identical or different, each represents a hydrogen atom or a radical

  alkyl or hydroxyalkyl containing from 1 to 3 carbon atoms.

  As nonlimiting examples of hydrophilic monomers of formula (II),

  there may be mentioned acrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-

  dimethyl-acrylamide, N-methyl-N-ethyl-acrylamide, N-hydroxymethylacrylamide,

  N- (3-hydroxypropyl) -acrylamide, N- (2-hydroxyethyl) -acrylamide, methacryla-

  mide, N-methyl-methacrylamide, N-ethyl-methacrylamide, N, Ndimethyl-

  methacrylamide, N-hydroxymethyl-methacrylamide, N- (3hydroxypropyl) -metha-

  crylamide and N- (2-hydroxyethyl) -methacrylamide.

  Acrylamide, methacrylamide and their N-substituted derivatives described above

  above will be chosen preferentially and more particularly acrylamide and methacrylamide. The content of non-ionic hydrophilic monomers (a) in the polymer

  can range from 50 to 98% by weight, preferably from 70 to 95% by weight, and more

  especially from 75 to 90% by weight.

  The fluorinated monomers (b) are monomers comprising a perfluoroalkyl radical, linear or branched, containing from 2 to 20 carbon atoms. The acrylates or methacrylates of fluorinated alcohols corresponding to the following general formula are preferably chosen:

CH2 = CR4 (111)

  COO-B - Rf in which Rf represents a linear or branched perfluoroalkyl radical containing from 2 to 20, preferably from 4 to 16 carbon atoms, R4 represents a hydrogen atom or a methyl radical, B represents a chain bivalent linked to O by a carbon atom and possibly comprising one or more oxygen atoms,

  sulfur and / or nitrogen. Mention may be made, without limitation, of acrylates or methacry-

  lates of fluorinated alcohols corresponding to the following formulas: Rf - CH2) n- (X) p - (CH2) m-OH Rf - (CH2) r (OCH2CH2) q-OH Rf - CH = CH- (CH2 ) m-OH in which Rf has the same meaning as in formula (111), X represents an oxygen or sulfur atom, or a group -COO-, -OCO-, -CONR5-, -SO2NR5-, R5 denoting a hydrogen atom or a methyl or ethyl radical, n represents an integer ranging from 0 to 20 (preferably equal to 0 or 2), p is equal to 0 or 1, the symbols m, q and r, identical or different, each represents an integer ranging from 1 to 20 (preferably equal to 2 or 4), n not being zero if

  X is an oxygen or sulfur atom or a group -OCO-.

  Preferably, the acrylates or methacrylates of fluorinated alcohols corresponding to the following formulas are used: Rf-CH2CH2-OH or Rf-CH2CH2-SO2NR5-CH2CH2-OH

  in which Rf and R5 have the same meaning as above.

  The content of fluorinated monomers (b) in the polymer can range from 2 to 25% by weight, preferably from 5 to 20% by weight, and more particularly from 7 to 15%

in weight.

  As examples of hydrophilic ionic or ionizable monomers by variation of the pH (c) which can optionally be used in the context of the invention, there may be mentioned, without implying any limitation: - acrylic acid, methacrylic acid and their salts alkali metals or quaternary ammonium ions; - mono-olefinic derivatives of sulfonic acid and their alkali metal salts such as, for example, sodium ethylenesulfonate, sodium styrenesulfonate and 2-acrylamido-2-methyl-propanesulfonic acid;

  - vinylpyridinium halides such as, for example 4- chloride

  vinylpyridinium; - the acrylates or methacrylates of amino alcohols corresponding to the following formulas: HO-Y-NR6R7 or HO - Y-NGR6R7R8, AG in which the symbols R6, R7 and R8, identical or different, each represent an alkyl or hydroxyalkyl radical containing I to 4 carbon atoms, Y represents an alkylene or hydroxyalkylene radical containing from 1 to 4 carbon atoms, and AE) is any monovalent anion; - the acrylates or methacrylates of cyclic amino alcohols such as, for example

  example, piperidino-2-ethanol and (pyrrolidinyl-1) -2-ethanol.

  It is possible to incorporate one or more ionic or ionizable hydrophilic monomers by variation of the pH (c); their content in the polymer can range from 0 to

  % by weight, that is to say that these monomers are not essential. However

  dant, having an ionic or ionizable character, they contribute to a better solubi-

  polymers according to the invention in water and it is preferred to incorporate them into a

  content varying from 2 to 25% by weight, preferably between 5 to 15% by weight.

  The hydrophilic fluoropolymers according to the invention are prepared by poly-

  merisation in a precipitating medium, in the absence of surfactant or any other stabilizing agent. The polymerization in a precipitating medium leads to better homogeneity of the chain length of the final product, that is to say a low polymolecularity; it also gives access, depending on the choice of solvent, to molecular weights

  much lower than in the case of polymerization in aqueous solution.

  Thus, it is not necessary to use transfer agents such as alkyl mercaptans to regulate the length of the chains; this advantage can be exploited if one wants products having low molecular weights, therefore products whose aqueous solutions are weakly viscous. Obtaining

  low molecular weights for hydrophilic fluoropolymers allows prepa-

  r aqueous solutions of low viscosity; this is important for the use of polymers in multipurpose fire-fighting foam concentrates o, for reasons

  of implementation, preferably low viscosities are sought.

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  The fluorine content of the hydrophilic polymers according to the invention is not critical.

  than. However, when the fluorine level is too high, the solubility of the polymers

  decreases, which creates implementation problems. In addition, the monomers

  Since fluorinated resins are very expensive compared to non-fluorinated hydrophilic monomers, it is desirable to use them as little as possible while having good performance. To have a good compromise between cost, solubility and efficiency, the fluorine content can be understood, by weight, between 1 and 15%, preferably between 2 and 10% and

  more particularly between 3 and 8%.

  The polymerization reaction takes place in an organic solvent in which the monomers and the radical initiator are perfectly soluble and in which the polymer obtained is insoluble, so that it precipitates during its formation. The polymerization solvent preferably has a short hydrocarbon chain such as acetonitrile and lower alcohols. The choice of polymerization solvent depends on the nature of the monomers (a), (b) and (c); it is essential that at the start of the reaction all the reagents are perfectly soluble

  in the solvent at a temperature corresponding to that of the start of the polymerization

  tion. The total concentration of the monomers in the solvent is advantageously between 0.5 and 3 mole / liter, preferably between 1 and 2 mole / liter. The solvent is preferably chosen from lower alcohols containing from 1 to 4 atoms of

  carbon such as, for example, methanol, ethanol, isopropanol or tertiobuta-

  nol. The reaction can take place in batch or in casting, the monomers (a), (b) and

  (c) which can be introduced independently into the reactor at different times

  rents. The radical initiator can be an azo type initiator such as, for example, azd-bis-isobutyronitrile or 4,4'-azo-biscyanopentanoic acid, as well

  than their derivatives having a hydrocarbon or perfluoroalkylated side chain.

  The preparation of azo initiators having a perfiuoroalkylated chain is

described in reference [13].

  The initiator can also be of peroxide type such as, for example, peroxy

  dicyclohexyl di-carbonate, benzoyl peroxide or di-tertiary peroxide

  butyl. It can also be a perester having a hydro-

  carbonaceous or perfluoroalkylated. The preparation and use of perfluoroal initiators

  kyl peresters is described in references [14] and [15].

  The concentration of the initiator can vary from 0.1 to 10 mol% relative to the total number of moles of monomers, but more particularly between 0.6 and 2%. Depending on the type of radical initiator used and the boiling point of the

  solvent, the polymerization temperature is between 50 and 100 C, preferably

  between 70 and 90 C. The reaction can, for example, be carried out at reflux of the solvent -g9; in this case, the refrigerant condenses and returns the solvent in the form

  liquid in the reaction medium. The addition of the radical initiator can be carried out

  killed at once at the start of the reaction, but we prefer to add it in several

  fractions or else in casting as this allows better incorporation of the mono-

  fluorinated mother in the polymer. It is preferable to use the initiator

  radicals already in solution and in this case use the reaction solvent.

  At the end of the reaction, the hydrophilic fluoropolymer according to the invention can be recovered in solid form by filtration. The reaction solvent can also be removed from the reaction medium by evaporation and replaced with water so as to obtain the

  polymer according to the invention in the form of an aqueous solution.

  The hydrophilic fluoropolymers according to the invention lower the surface tension of aqueous solutions; they have good foaming power and can,

  for example, to be used as additives in poly-fire fighting foam concentrates

  valents, that is to say fire-fighting foam concentrates intended to fight hydrocarbon fires such as gasolines, oils, diesel, fuel, heptane, hexane, cyclohexane, or fires polar liquids such as alcohols (for example

  e.g. methanol, ethanol and isopropanol), ketones (e.g. dimer-

  thylketone and methyl isobutyl ketone), esters (e.g. n-butyl acetate)

  and ethers (e.g. methyltertiobutyl ether).

  Fire-fighting foam concentrates are liquid compositions intended for

  fight fires of combustible liquids (hydrocarbons and / or polar liquids).

  At the time of use, the foam concentrates are diluted in tap water or sea water, generally at a volume concentration of 3% (i.e. 3 volumes of foam concentrate for 97 volumes of water ) or 6% (6 volumes of foam concentrate for 94 volumes of water) but also, and more rarely, 1% (1 volume of foam concentrate for 99 volumes of water). After dilution of the foam concentrates, the quantity of active ingredients necessary to satisfy the minimum extinguishing performance required being identical in all cases of dilution, the foam concentrates which can be diluted to 3% are therefore twice as concentrated as those which can be diluted to 6%; they allow users to store lesser amounts of foam concentrate, save space and reduce storage costs. The foaming solution is obtained by diluting the foam concentrate with water. This foaming solution passes through a fire hose where mechanical agitation takes place with the incorporation of air, which generates a fire-fighting foam

  used to fight fires of combustible liquids.

  When the polymers according to the invention are integrated into the emulsifiers, they

  improve the stability of fire-fighting foams on polar liquid and therefore their perfor-

  fire extinguisher on these types of fires. Their content in foam concentrates can range

  generally from 0.1 to 10% by weight and preferably from 0.2 to 5% by weight.

  The emulsifiers in which the hydrophilic fluoropolymers can be incorporated are of two types, depending on the origin of their foaming base. A distinction is made between synthetic foam concentrates whose foaming base consists of at least one hydrocarbon-based surfactant and protein foam concentrates whose foaming base consists of a hydrolyzate of animal proteins. These two types

  foam concentrates may contain, depending on their destination, one or more surfactants

  fluorinated active ingredients, one or more foam stabilizing co-solvents, a high molecular weight hydrophilic polymer of the polysaccharide type with a thixotropic nature and

  alcoophobic, anti-freeze agent, anti-corrosion agent, preservative, stabilizer

  pH value, mineral salts whose cation is divalent, such as, for example, the ion

magnesium or calcium ion.

  The versatile fire-fighting foam concentrates containing a hydrophilic polymer according to the invention are used to combat fires of hydrocarbons and polar liquids. Their performance can be assessed by means of the following tests: Spreading Expansion (or expansion rate) is the ratio of the volume of foam produced from an aqueous solution of 3 or 6% foam concentrate to the volume of initial liquid. To determine the expansion, we introduce into a test tube of 1 liter ml of aqueous solution with 3 or 6% foam concentrate, then the solution is beaten

  for one minute at the rate of one beat per second using a circular piston

  perforated sheet (30 holes of 5 mm in diameter representing 25% of the surface) and fixed in its center to a metal rod. We measure the volume in milliliters of foam

  obtained and, by dividing by 100, we obtain the amount of expansion.

  Stability of the foam on polar liquid 100 ml of acetone are poured into a crystallizer with an internal diameter of 11.8 cm. On the other hand, the foam concentrate is diluted to 3 or 6% in tap water and the foam is produced using an electric mixer for 2 minutes. 10 + 2 g of foam are poured onto the acetone and the timer is started. Note the total disappearance time of the foam. The most efficient foam concentrates on polar liquid are those for which the total disappearance time of the foam is as long as possible. Extinguishing efficiency on polar liquid 150 ml of acetone are poured into a circular metal container 12 cm inside diameter. On the other hand, an aqueous solution composed of the emulsifier diluted to 3 or 6% in city water is prepared. There is a rotary agitator composed of a motor and a metal rod at the end of which are fixed blades which produce a mechanical action when the rod is in rotation; the rotation speed is adjustable from 0 to 2800 rpm. The rod is introduced at the bottom of a

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  cylindrical container with an inlet at the bottom and an outlet at the top. A metering pump transfers the aqueous solution to the bottom of the cylindrical container through the inlet port; upon contact with the rotating blades, foam is produced which, as it forms, is evacuated through the outlet orifice. The pump flow and the rod rotation speed are adjusted so that foam is produced continuously with a fixed foam flow equal to

36 + 2 g / min.

  When the foam flow is stabilized, the acetone is ignited. After combustion of the acetone for 90 seconds, the foam is poured inside the metal container by a single point located on the circumference. When the acetone is completely extinguished, the extinction time is noted. The amount of foam spilled to extinguish the fireplace is calculated by multiplying the time by the flow rate. The most efficient foam concentrates on polar liquid are those for which the

  the amount of foam spilled is as small as possible.

EXAMPLES

  In the following examples which illustrate the invention without limiting it, the

  the percentages indicated are expressed by weight and certain constituents used are desi-

  identified, for simplicity, by the following abbreviations: AI = 2- (perfluorooctyl) ethyl acrylate of formula:

CH2 = CH-COO-- C2H4 --- <CF2) 7CF3

  A2 = mixture of 2- (perfluoroalkyl) ethyl acrylates of formula: CH2 = CHCOO-C2H4 - (CF2) nCF3 having the following composition by weight: n%

1

7 63

9 25

11 9

13 3

  A3 = mixture of 2- (perfiuoroalkyl) ethyl methacrylates of formula: CH2 = C (CH3) COO0C2H4 - (CF2) nCF3 -12 - having the same weight composition as A2 B1 = acrylic acid of formula:

CH2 = CH-COOH

  B2 = N- [2- (acryloyloxy) ethyl] -N, N, N-trimethylammonium chloride of formula: CH2 = CH-COO-C2H4-Ne (CH3) 3, ClE 'Cl = 27% hydroalcoholic solution of the fluorinated betaine of formula: CH3 I

  C6F13 - CH2CH2 - SO2NH - CH2CH2CH2 - NG - CH2 - COO

CH3

EXAMPLE1

  a) Synthesis: In a 1 liter reactor equipped with a thermometer, a reflux condenser, a nitrogen inlet and a mechanical stirrer, 13.9 g (0.196 mole) of acrylamide are dissolved , 3.53 g (0.049 mole) of B1 and 2.96 g (0.005 mole) of mixture A3 in 210 ml of isopropanol. Stirring is started, then the reaction medium is brought to the temperature of 80 ° C., under nitrogen circulation. A solution of 0.41 g (0.0025 mol) of azo-bis-isobutyronitrile in ml of isopropanol is introduced into the reactor. A white precipitate forms quickly and the reaction medium is maintained at 80 ° C. for 90 minutes. It is again introduced into the reactor

  a solution of 0.41 g (0.0025 mole) of azo-bis-isobutyronitrile in 20 ml of isopro-

  panol. The reaction medium is still maintained at 80 ° C. for 30 minutes. After cooling to room temperature, the polymer is recovered by filtration, washed successively with isopropanol and acetone, then dried. We recover the polymer

  in the form of a powder with 100% active material. The measured fluorine level experienced

  mentally on the product obtained is 7.4%.

  b) Evaluation in synthetic fire-fighting foam concentrate:

  50 g of a 1% aqueous polysaccharide solution, prepared by addi-

  tion in water at room temperature of the Actigum CX9YL1 polysaccharide from System Bio-lndustries in the form of a powder with vigorous stirring, 0.68 g of the hydrophilic fluoropolymer prepared above, 15 g, are added at room temperature with moderate stirring. of butyl diglycol and 5 g of solution Cl. Then make up to g by adding water. We obtain a fire-fighting foam concentrate which is diluted to 3% -13-

  with city water. The resulting solution, subjected to the tests described above.

  has the following characteristics: Spread 6.7 Stability of the foam on acetone: 210 seconds Extinguishing efficiency on acetone: Extinguishing time: 182 seconds Mass of foam spilled: 109 grams c) Evaluation in protein fire-fighting foam concentrate:

  To 94 g of a protein hydrolyzate with 35% dry extract is added temporarily.

  rature ambient and with moderate stirring 2 g of the hydrophilic fluoropolymer prepared above and 4 g of solution C1. A protein fire-fighting foam concentrate is obtained which is diluted to 6% with tap water. The resulting solution, subjected to the tests described above, has the following characteristics: Spread 9 Stability of the foam on acetone: 870 seconds Extinguishing efficiency on acetone: Time of extinction: 58 seconds Mass of spilled foam: 35 grams

EXEMP.LE2

  a) Synthesis: In a 1 liter reactor equipped with a thermometer, a reflux condenser, a nitrogen inlet and a mechanical stirrer, 17.4 g are dissolved.

  (0.245 mole) of acrylamide and 2.96 g (0.005 mole) of mixture A3 in 230 ml of iso-

  propanol. The stirring is started then the reaction medium is brought to the temperature.

  80 C, under nitrogen circulation. A solution of 0.41 g (0.0025 mole) of azo-bis-isobutyronitrile in 20 ml of isopropanol is introduced into the reactor. A white precipitate forms quickly and the reaction medium is maintained at 75 ° C. for minutes. After cooling to room temperature, the polymer is recovered by filtration, washed successively with isopropanol and acetone, then dried. The polymer is recovered in the form of a powder containing 100% active material. NMR analysis of the proton on the product obtained reveals an unsaturation rate of less than 0.5% of unreacted double bonds. The fluorine level measured experimentally is

4.4%.

  b) Evaluation in synthetic fire-fighting foam concentrate:

  We proceed as in Example 1 (paragraph b), but we replace the poly-

  hydrophilic fluorinated mother of Example 1 with 1.14 g of the hydrophilic fluoropolymer prepared above. A fire-fighting foam concentrate is obtained which is diluted to 3% with

- 14 -

  city water. The resulting solution, subjected to the tests described above, has the following characteristics: Spreading 6.3 Stability of the foam on acetone: 80 seconds Extinguishing efficiency on acetone: Time of extinction: 158 seconds Mass of spilled foam: 95 grams c) Evaluation in protein fire-fighting foam concentrate:

  To 92.6 g of a protein hydrolyzate with 35% dry extract is added temporarily.

  ambient temperature and with moderate stirring 3.4 g of the hydrophilic fluoropolymer prepared above and 4 g of Cl solution. A protein fire-fighting foam concentrate is obtained which is diluted to 6% with tap water. The resulting solution, subjected to the tests described above, has the following characteristics: Spread: 8 Stability of the foam on acetone: 720 seconds Extinguishing efficiency on acetone: Time of extinction: 70 seconds Mass of spilled foam: 42 grams

EXAMPLE

  a) Synthesis: The procedure is as in Example 2 (paragraph a), but the mixture A3 is replaced by 2.87 g (0.005 mole) of mixture A2 and isopropanol with the same volume of ethanol. The polymer is recovered in the form of a powder containing 100% active material. NMR analysis of the proton on the product obtained reveals an unsaturation rate of less than 0.5% of unreacted double bonds. Fluorine level

  measured experimentally is 3.5%.

  b) Evaluation in synthetic fire-fighting foam concentrate:

  We proceed as in Example 1 (paragraph b), but we replace the poly-

  hydrophilic fluorinated mother of Example 1 with 1.43 g of the hydrophilic fluoropolymer prepared above. A fire-fighting foam concentrate is obtained which is diluted to 3% with tap water. The resulting solution, subjected to the tests described above, has the following characteristics: Spreading 5.9 Stability of the foam on acetone: 157 seconds Extinguishing efficiency on acetone: Time of extinction: 186 seconds Mass of spilled foam: 112 grams - 15-

EXAMPLE 4

  a) Synthesis: In a 1 liter reactor equipped with a thermometer, a reflux condenser, a nitrogen inlet and a mechanical stirrer, 21.3 g (0.3 mole) are dissolved. 'acrylamide, 5 g (0.01 mole) of A1, 1.8 g (0.025 mole) of B1 and 3.9 g (0.02 mole) of B2 in 190 ml of isopropanol. Stirring is started then the reaction medium is brought to the temperature of 75 ° C., under nitrogen circulation. We

  introduced into the reactor a solution of 0.41 g (0.0025 mole) of azobis-isobutyroni-

  trile in 30 ml of isopropanol. A white precipitate forms quickly and the reaction medium is maintained at the reflux temperature of isopropanol for one hour. A solution of 0.41 g (0.0025 mole) of azo-bis-isobutyronitrile in 30 ml of isopropanol is again introduced into the reactor. The reaction medium is still

  maintained at the reflux temperature of isopropanol for 4 hours. After cooling

  At room temperature, the polymer is recovered by filtration, washed successively with isopropanol and acetone and then dried. We recover the polymer

  in the form of a powder with 100% active material. The measured fluorine level experienced

  mentally on the product obtained is 7.2%.

  b) Evaluation in synthetic fire-fighting foam concentrate:

  We proceed as in Example 1 (paragraph b), but we replace the poly-

  hydrophilic fluorinated mother of Example 1 with 0.49 g of the hydrophilic fluoropolymer prepared above. A fire-fighting foam concentrate is obtained which is diluted to 3% with tap water. The resulting solution, subjected to the tests described above, has the following characteristics: Spread: 5.9 Stability of the foam on acetone: 27 seconds Extinguishing efficiency on acetone: Time of extinction: 240 seconds Mass of spilled foam: 144 grams

EXAMPLE-5

  a) Synthesis: In a 1 liter reactor equipped with a thermometer, a reflux condenser, a nitrogen inlet and a mechanical stirrer, 21.3 g (0.3 mole) are dissolved. 'acrylamide, 5 g (0.01 mole) of A1 and 3.6 g (0.05 mole) of B1 in 190 ml of ethanol. Stirring is started then the reaction medium is brought to the temperature of 75 ° C., under nitrogen circulation. A solution of 0.41 g (0.0025 mol) of azo-bis-isobutyronitrile in 30 ml of ethanol is introduced into the reactor. A

  white precipitate forms quickly and the reaction medium is maintained at room temperature.

- 16 -

  rature of reflux of ethanol, for one hour. A solution of 0.41 g (0.0025 mole) of azobisisobutyronitrile in 30 ml of ethanol is again introduced into the reactor. The reaction medium is still maintained at the reflux temperature of

  ethanol for 4 hours. After cooling to room temperature, the poly-

* mother is recovered by filtration, washed successively with ethanol and acetone then

  dried. The polymer is recovered in the form of a powder containing 100% active material.

  The fluorine content measured experimentally on the product obtained is 7.6%.

  b) Evaluation in synthetic fire-fighting foam concentrate:

  We proceed as in Example I (paragraph b), but we replace the poly-

  hydrophilic fluorinated mother of Example 1 per 2 g of the hydrophilic fluoropolymer prepared above. A fire-fighting foam concentrate is obtained which is diluted to 3% with tap water. The resulting solution, subjected to the tests described above, has the following characteristics: Spread 7.3 Stability of the foam on acetone: 480 seconds Extinguishing efficiency on acetone: Time of extinction: 72 seconds Mass of spilled foam: 43 grams c) Evaluation in protein fire-fighting foam concentrate:

  To 88.4 g of a protein hydrolyzate containing 44% dry extract,

  ambient rature and with moderate stirring 3.6 g of the hydrophilic fluoropolymer prepared above and 8 g of solution C1. A protein fire-fighting foam concentrate is obtained which is diluted to 3% with tap water. The resulting solution, subjected to the tests described above, has the following characteristics: Spread 7.7 Stability of the foam on acetone: 780 seconds Extinguishing efficiency on acetone: Time of extinction: 57 seconds Mass of spilled foam: 34 grams

EXAMPLES 6 to 9

  By proceeding as in Example 4 (paragraph a) with the synthetic solvent and the composition of monomers indicated in the table below, other hydrophilic fluoropolymers according to the invention were synthesized. The solvent used

  to wash the polymer obtained is of the same nature as the synthetic solvent.

  -17- Example Acrylamide solvent Fluorinated monomer Other synthetic monomer 6 Isopropanol 21.3g (0.3 mole) AI: 5g (0.01 mole) B2: 7.8g (0.04 mole)

  7 Ethanol 25g (0.35 mole) AI: 5g (0.01 mole) -

  8 Ethanol 21.3g (0.3 mole) A2: 4.88g (0.0086 BI: 3.6g (0.05 mole) ________ _______ (0.3mole) _5, 6 e3 9 0 m 9 Isopropanol 21.3g (0.3 mole) A3: 5g (0.0086 mole) BI: 3.6g (0.05 mole) Isopropanol 21.3g (0.3 mole) A2: 4.88g (0.0086 BI: 3.6g (0.05 mole) mole) EXAMPLE 11 (comparative) A fire-fighting foam concentrate is prepared by proceeding as in Example 1

  (paragraph b), but without incorporating hydrophilic fluoropolymer according to the invention.

  A fire-fighting foam concentrate is obtained which is diluted to 3% with tap water. The

  resulting solution, subjected to the tests described above, has the characteristics

  following techniques: Spread 6.2 Stability of the foam on acetone: <20 seconds Extinguishing efficiency on acetone: Extinguishing time: 266 seconds Mass of spilled foam: 160 grams EXAMPLE 12 (comparative) In a 1 liter reactor equipped with 17.2 g of thermometer, reflux condenser, nitrogen inlet and mechanical stirrer

  (0.243 mole) of acrylamide and 1.35 g (0.007 mole) of B2 in 210 ml of isopropanol.

  Stirring is started then the reaction medium is brought to the temperature of 78 ° C., under nitrogen circulation. A solution of 0.41 g (0.0025 mol) of azo-bis-isobutyronitrile in 20 ml of isopropanol is introduced into the reactor. A white precipitate forms quickly and the reaction medium is maintained at 78 ° C. for minutes. After cooling to room temperature, the polymer is recovered by filtration, washed successively with isopropanol and acetone, then dried. A product is obtained in accordance with the invention which is in the form of a powder.

100% active ingredient.

- 18 -

  EXAMPLE 13 (comparative) In a 1 liter reactor equipped with a thermometer, a reflux condenser, a nitrogen inlet and a mechanical stirrer, 34.4 g (0.48 mole) are dissolved. acrylamide and 2.9 g (0.015 mole) of B2 in 420 ml of acetonitrile. Stirring is started then the reaction medium is brought to the temperature of 78 ° C., under nitrogen circulation. A solution of 0.82 g (0.005 mole) of azo-bis-isobutyronitrile in 40 ml of acetonitrile is introduced into the reactor. A white precipitate

  forms rapidly and the reaction medium is maintained at 80 ° C. for 30 minutes.

  After cooling to room temperature, the polymer is recovered by filtration, washed successively with acetonitrile and acetone, then dried. A product is obtained in accordance with the invention which is in the form of a powder for

% of active ingredient.

  The surface tension and foaming power of aqueous solutions contains

  The non-fluorinated polymers prepared in Examples 12 and 13 were compared with those of the polymers according to the invention. For this, solutions were prepared at I g / liter of the various hydrophilic polymers in demineralized water, then on each solution the surface tension was measured at 20 ° C. by stretching the film using a platinum caliper. and the foaming power according to the Ross-Miles method (observation of the volume of foam after 30 seconds), the principle of which is described in the international standard ISO 696. The results obtained are collated in the following table: Polymer of Fluorine Rate Tension Power Example n of the foaming surface polymer (ml) l ____ ___ _ (%) (mN / m) None - 72.5 no foam

3 3.5 52.0 210

8 7.1 53.0 200

7.1 41.7 220

  12 Comp. 0 72.5 no foam 13 Comp. 0 62.0 no foam

  Unlike the hydrophilic fluoropolymers according to the invention, the poly-

  non-fluorinated mothers of Comparative Examples 12 and 13 have no soft properties

  health. On the other hand, the lowering of the surface tension obtained with the polymers

  -19- fluorinated res according to the invention is more important than in the case of polymers of

comparative examples 12 and 13.

REEERENES

  [1] A. Hill, F. CANDAU and J. Selb - Macromolecules (1993), 26, p.4521.

  [2] C.L. McCormick, T. Nonaka and C.B. Johnson - Polymer (1988), 29, p.731.

  [3] K.C. Dowling and J.K. Thomas - Macromolecules (1990), 23, p. 1059.

  [4] Y.X. Zhang, A.H. Da, T.E. Hogen-Esch and G.B. Butler - ACS - Symp. Ser. (1991),

467, p.159.

  [5] Y.X. Zhang, A.H. Da, T.E. Hogen-Esch - Journal or Polymer Science; Part C:

  PolymerLetters (1990), vol. 28, p.213.

  [6] F.S. Hwang and T.E. Hogen-Esch - PolymerPreprints (1993), 34 (1), p. 405.

  [7] T.E. Hogen-Esch, M. Yassini, Y.-X. Zhang, F. Huang, E.J. Amis and T. Seery -

  Polymer Preprints (199Q), 31 (2), p.460.

  [8] Y.X. Zhang, A.H. Da, T.E. Hogen-Esch and G.B. Butler -Journal or Polymer

  Science; Part A: Polymer Chemistry (1992), vol. 30, p. 1383.

  [9] X. Xie and T.E. Hogen-Esch - Macromolecules (1996), 29, p. 1734.

  [10] M. Yassini and T.E. Hogen-Esch - PolymerPreprints (1994), 35 (1), p. 478.

  [11] Y.X. Zhang, A.H. Da and T.E. Hogen-Esch - Polymer Preprints (1989), 30 (2),

p.338.

  [12] F.A. Abdel-Mohdy, A. waly, A. Higazy and A. Hebeish - Pigment & Resein

Technology (1994), 23 (2), p. 10.

  [13] J.M. Bessiere, B. Boutevin, O. Loubet - Polymer Bulletin (1993), 30, p.545.

  [14] H. Sawada - Review on Heteroatom Chemistry (1993), 8, p.205.

  [15] H. Sawada, Y. Minoshima, T. Hiromitsu - Joumrnal of Fluonrine Chemistry (1993),

(1-2). p. 169.

-20 -

Claims (12)

  1. Fluorinated hydrophilic polymer obtained by radical polymerization, in a precipitating medium, of a mixture of monomers composed by weight of: (a) 50 to 98% of at least one non-ionic hydrophilic monomer;   (b) 2 to 25% of at least one monomer comprising a perfiuoroal- radical   kyle, linear or branched, containing from 2 to 20 carbon atoms; and (c) 0 to 30% of one or more ionic or ionizable hydrophilic monomer (s). 2. Hydrophilic fluoropolymer according to claim 1, in which one chooses   the non-ionic hydrophilic monomer (s) among acrylamide, methacry-   lamide and their N-substituted derivatives of the following general formula: CH2 = CR1-CONR2R3 (II) in which R1 represents a hydrogen atom or a methyl radical, the   symbols R2 and R3, identical or different, each represent a hydro-   gene or an alkyl or hydroxyalkyl radical containing from 1 to 3 carbon atoms 3. Hydrophilic fluorinated polymer according to claim 1 or 2, in which the fluorinated monomer (s) (b) are acrylic or methacrylic monomers corresponding to the following general formula: CH2 = CR4 (111)   COO-B-Rf in which Rf represents a linear or branched perfluoroalkyl radical containing   from 2 to 20, preferably from 4 to 16 carbon atoms, B represents a chain-   bivalent ment linked to O by a carbon atom and possibly comprising one or more oxygen, sulfur and / or nitrogen atoms and R4 represents a hydrogen atom or a methyl radical.   4. Hydrophilic fluoropolymer according to claim 3, in which B is a divalent radical CH2CH2 or CH2CH2NR5SO2CH2CH2 in which R5 represents   a hydrogen atom or a methyl or ethyl radical. -21 -   5. Hydrophilic fluoropolymer according to one of claims 2 to 4, prepared   by radical polymerization in a precipitating medium in acetonitrile or in a   alcohol containing from 1 to 4 carbon atoms.   6. Hydrophilic fluoropolymer according to claim 5, prepared by polymer-   radicalization in a precipitating medium in ethanol or isopropanol.   7. Hydrophilic fluoropolymer according to one of claims I to 6, prepared   from a mixture of monomers composed by weight of 70 to 93% of monomer-   res (a), from 5 to 20% of monomers (b) and from 2 to 25% of monomers (c).   8. Hydrophilic fluoropolymer according to claim 7, prepared from a mixture of monomers composed by weight of 75 to 88% of monomers (a), from 7 to   % of monomers (b) and 5 to 15% of monomers (c).   9. hydrophilic fluoropolymer according to one of claims 1 to 8, the   fluorine content is between 1 and 15% by weight, preferably between 2 and 10%, and   more particularly between 3 and 8%.   10. Hydrophilic fluoropolymer according to one of claims 1 to 9, prepared   by radical polymerization with an initiator concentration of between 0.1 and 10 mol% (preferably between 0.6 and 2 mol%) relative to the number   total moles of monomers (a), (b) and optionally (c).   11. Use of a hydrophilic fluoropolymer according to one of claims   1 to 10 in a versatile fire-fighting foam concentrate.   12. Versatile fire-fighting foam concentrate comprising by weight from 0.1 to 10%,   preferably from 0.2 to 5%, of a hydrophilic fluoropolymer according to one of the claims cations 1 to 10.